Oleg Dirksen et al / St Andrews University
The mysterious eruption occurred at the Zavaritskii volcano on the island of Simushir and created a 3 km wide caldera, revealing spectacular red, black and white layers made up of past eruptive deposits.
The identity of the mysterious volcano responsible for a giant volcanic eruption that puzzled scientists for nearly 200 years has finally been found: it was the Zavaritskii volcano, on the remote and uninhabited island of Simushir, part of the Kuril Islands.
In 1831, a massive volcanic eruption released sulfurous gases into the atmosphere, reflecting sunlight and causing global cooling of around 1ºC.
This cold weather, well documented around the world, led to widespread crop failures and devastating famines.
The composer Felix Mendelssohn he even wrote about the catastrophic weather during his summer trip through the Alps in 1831: “Desolating weather, it rained again all night and all morning, it’s as cold as in winter, there’s already deep snow on the nearest hills…”
The 1831 eruption is Earth’s most recent “mysterious eruption.” Although scientists knew that this was an important event that caused climate change and social upheavalthe identity of the volcano responsible remained unknown and fiercely debated, until now.
In a new study, a team led by Will Hutchisona researcher at the University of St Andrews, analyzed the ice core records of the event 1831 and identified a “perfect fingerprint match” of the ash deposits.
The results were presented in an article published last week in the journal Proceedings of the National Academy of Sciences.
“It is only in recent years that we have developed the ability to extract microscopic fragments of ash from polar ice cores and perform detailed chemical analyses. They are incredibly tinyabout a tenth the diameter of a human hair”, explains Hutchison in one from the university.
Hutchison and his team were able to accurately date and match the ice core deposits to the Zavaritskii volcanoon the remote and uninhabited island of Simushir, part of the Kuril Islands.
These islands are a disputed territory between Russia and Japan. Currently controlled by Russia, they function as a strategic military post.
During the Cold War, in a plot reminiscent of a Bond film, the Soviets used Simushir as a secret base for nuclear submarinesmooring the ships in a flooded volcanic crater.
“We analyze ice chemistry with very high temporal resolution. This allowed us identify the exact moment of the eruptionin the spring/summer of 1831, confirm that it was highly explosive and then extract the small fragments of ash”, adds Hutchison.
“Finding the match took a long time and required extensive collaboration with colleagues in Japan and Russia, who sent us samples collected from these remote volcanoes decades ago,” says the researcher.
“The moment in the laboratory when we analyzed the two ash together, one from the volcano and the other from the ice core, it was a real eureka moment. I couldn’t believe the numbers were identical,” says Hutchison.
“After that, I spent a lot of time investigating the age and size of the eruption in the Kuril records to really convince myself that the correspondence was real“, he admits.
The results of the study make it possible to identify the Kuril Islands as a volcanic region little studied but extremely productive.
The volcano responsible for the 1831 eruption it was very remote, but there was a significant global non-climate impact and serious consequences for human populations.
Identifying the sources of these mysterious eruptions is crucial, as it allows scientists to map and monitor the regions of Earth most likely to produce volcanic events that change the climate.
“There are many volcanoes like this, which highlights the difficulty of predicting when or where the next large eruption might occur. As scientists and as a society, we have to think about coordinating the international response when the next major eruption occurs, like the one in 1831”, he concludes.
